Footwear, Insoles, Inserts, Kits and Methods

ABSTRACT

Footwear, insoles, inserts, kits and methods effective for acclimating a user&#39;s foot to a different heel-toe ramp and/or foot strike pattern are provided. Footwear, insoles, inserts and kits of the present disclosure have a region of adjustable thickness which allows the user to gradually change the heel-toe ramp of the user&#39;s foot, and/or gradually adapt to a new foot-strike pattern. Regions of adjustable thickness may include a layered pad, inserts of varying thicknesses which may be used with the footwear or insert, or a material having a thickness which changes with the rate of applied force.

FIELD

The field generally relates to footwear, and more particularly to insoles, kits, and methods for use with footwear.

BACKGROUND

Insoles, inserts, and other types of cushioning mechanisms are just a few of the products on the market directed to the well-being of the human foot. The human foot experiences repetitive stresses from bearing the weight of the human body on a daily basis, during a variety of activities, including walking, climbing, kicking, running, dancing and jumping.

The repetitive stresses experienced by the foot may lead to injury of the bones, joints, and the hundreds of muscles, tendons and ligaments present in the human foot, leg and/or back. III-fitting shoes, obesity, diseases such as arthritis or diabetes can lead to bone fractures, tissue inflammation and other injuries. Foot injuries can occur in any part of the foot including the heel, toes, metatarsal joints and arch. Treatment for, and prevention of, foot injuries or foot discomfort can benefit from the use of padding or cushioning systems. Padding or cushioning systems may be a part of the footwear design, or may be provided by the use of supplemental insoles or inserts.

For example, some shoes, such as shoes for athletes, frequently have cushioning in the heel to absorb the impact of the heel strike during running, and to otherwise minimize the stress on the heel. Additionally, supplemental insoles or inserts may be used with training shoes or other footwear to target particular areas of the foot to provide the desired padding, cushioning, alignment, and/or support of the foot. Various inserts and insoles are available to provide arch, heel, ball and toe support, to minimize pronation, and to address issues that arise from medical conditions.

For example, U.S. Pat. No. 7,774,883 is directed to orthopedic insoles which prevent the foot from bending excessively at the metatarsal joints. This configuration attempts to minimize stretching, cracking or other damage to the skin which may be slow to heal and may lead to painful wounds in people with diabetes. U.S. Pat. No. 7,788,826 is directed to a dynamic shock attenuation system which produces a proportional response to a wide range of impact forces. Despite the advances in the art, further advances are possible and desired.

SUMMARY

Disclosed herein are embodiments for footwear, removable insoles, inserts, kits and methods to configure and/or modulate the effective elevation of a user's heel relative to the elevation of the user's ball of foot and/or toe region. The desired elevation can be achieved during periods of load, such as standing, walking, running, and the like. In some embodiments, a footwear insole of adjustable thickness between a heel region and a non-heel region (such as a metatarsal, ball-of-foot, toe, and/or arch regions and the like) can be provided. The present embodiments can allow at least one of a portion of the heel region or a portion of the non-heel region (preferably the ball of foot/metatarsal region) to be configured to a desired elevation during such load events and even at rest.

Footwear and/or insoles and inserts having a region of adjustable thickness may be provided in some embodiments to at least a portion of the heel region, at least a portion of the metatarsal region, or both. In one approach, a region of adjustable thickness can comprise a layered pad with a plurality of padding layers, wherein removal or addition of a padding layer alters the thickness of the layered pad. The pads can be configured to be on either side of a base insole or insert, namely the side adjacent to or away from a user's foot. In another embodiment, the region of adjustable thickness can comprise a bracket for receiving inserts of varying thicknesses. An insert of a particular thickness may be interchanged with an insert of a different thickness in the bracket to change the thickness of the region of adjustable thickness. In yet another embodiment, the region of adjustable thickness can comprise a cavity within the insole. The cavity can be configured to receive inserts of varying thicknesses. An insert of a particular thickness may be interchanged with an insert of a different thickness in the cavity to change the thickness of the region of adjustable thickness. It is noted that the footwear itself may be configured to receive the layered pads, or the inserts of varying thickness by configuring the footwear with a bracket or cavity to receive the inserts of varying thickness.

A footwear kit for acclimating a user's foot to a desired heel-toe ramp is also provided. In one approach, the kit can have an insole or insert having at least one bracket, and at least one insert or a set of a plurality of inserts of varying thicknesses, which removably engage with the bracket. The inserts may be interchanged in a stepwise fashion to incrementally adjust the thickness of the region comprising the brackets. In another aspect, the kit can have an insole having at least one cavity, and at least one insert or a set of inserts of varying thicknesses which may be removably disposed within the cavity. The inserts can be interchanged in a stepwise fashion to incrementally adjust the thickness of the region comprising the cavity. By adjusting the thickness of various portions of the insole or insert, the user can adjust the effective heel-toe/ball of foot ramp during load. In other approaches, the footwear kit comprises footwear configured with at least one bracket or cavity to receive at least one insert or a plurality of inserts of varying thicknesses.

Also provided by the present disclosure is a method for acclimating a user's foot to a target heel-toe ramp, comprising the step of gradually adjusting the heel-toe ramp of an insole from a starting heel-toe ramp to a target heel-toe ramp. This adjustment can be made, for example, by varying the thickness of the insole in gradually decreasing or increasing increments. The incremental percentage change in thickness may, for example, be in ten percent increments. In other embodiments, the change in thickness may be, for example, in 2 mm increments. The gradual adjustment of the heel-toe ramp angle can include providing an insole having a heel region and/or a metatarsal region wherein the thickness of at least one of a portion of the heel region or a portion of the metatarsal region is adjustable in thickness. The thickness of the portion of the heel region or the portion of the metatarsal region can be adjusted to provide for a first desired heel-toe ramp. The insole or insert is then used with footwear for a first duration of time sufficient for the user's foot to acclimate to the first desired heel-toe ramp. The thickness of the portion of the heel region or the portion of the metatarsal region is again adjusted to provide for a second desired heel-toe ramp different from the first desired heel-toe ramp. The insole is then used with the footwear for a second duration of time sufficient for the user's foot to acclimate to the second desired heel-toe ramp. Each adjustment may be an incremental adjustment in a direction towards the target heel-toe ramp. In other approaches, the method for acclimating a user's foot to a target heel-toe ramp comprises gradually adjusting the heel-toe ramp of footwear from a starting heel-toe ramp to a target heel-toe ramp using any of the adjustment mechanisms described above.

Also provided by the present disclosure is a method for acclimating a user's foot from a first foot-strike pattern to a second foot-strike pattern comprising providing an insole with a heel region and a metatarsal region wherein at least a portion of the heel region of a portion of the metatarsal region is a region of adjustable thickness having a thickness which changes in response to the rate of force applied. The region of adjustable thickness is located at a first location where the foot first strikes the ground during the first foot-strike pattern. The user uses the insole with footwear for a first duration of time sufficient for a user's foot to acclimate to a second foot-strike pattern having a second location where the foot first strikes the ground.

Numerous other advantages and features of the present disclosure will be become readily apparent from the following detailed description and the embodiments therein, from the claims and from the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a bottom perspective view of an insole according to one exemplary embodiment;

FIG. 2 is a view similar to FIG. 1 which illustrates an adjustment of the thickness of the insole of FIG. 1;

FIG. 3 is a bottom perspective view of an insole according to another embodiment;

FIG. 4 is a perspective view of components of a kit including the insole of FIG. 3;

FIG. 5 is a bottom perspective view of an insole according to another embodiment;

FIG. 6 is a sectional side view of the insole of FIG. 5 taken along lines VI-VI;

FIG. 7 is a perspective view of components of a kit including the insole of FIG. 5;

FIG. 8 is a bottom perspective view of a heel insert according to a one exemplary embodiment.

FIG. 9 is a bottom perspective view of a % insole according to one embodiment;

FIG. 10 is a bottom perspective view of an insole according to yet another embodiment;

FIG. 11 is a sectional side view of the insole of FIG. 10 taken along lines XI-XI; and

FIG. 12 is a side elevational view of an insole according to another embodiment.

DETAILED DESCRIPTION

There is growing interest the biomechanics of the movement of the human feet and body during barefoot running or running with footwear having little or no heel-toe ramp angle relative to the surface on which the runner is running or otherwise ambulating. In these minimalist conditions there is less or no cushioning of the feet and the body to the ground surface during standing or ambulation (such as running and walking) compared to a typical training shoe, which has more cushioning and heel elevation. For example, a typical training shoe has a heel-toe ramp resulting from heel-toe drops of between 12 mm to 15 mm, or sometimes even more. It is noted that herein the heel-toe ramp is defined as the change in elevation of footwear from at least a portion of the heel to at least a portion of a non-heel region, with and/or without a load. The non-heel region can include any portion of the foot that is distal to the heel, such as the arch, metatarsus, ball-of-foot, toes, and the like and combinations thereof. A load can include the stationary weight of a user, or effective weight applied to the footwear during a user's foot strike (ambulation), such as when running and/or walking and the like. In some embodiments the heel and non-heel portion elevation change can be measured where a center of load from the human heel and the center of load from the ball of the human foot occur.

Running with minimal or reduced heel cushioning (compared to the heel cushioning provided by more traditional training shoes) allows for a lower heel-to-toe ramp. Studies have shown that the lower heel-toe ramp allows the foot to move more naturally and to provide a more efficient running posture. Such studies emphasize the benefits of running minimally and have caused an increase in the popularity of minimalist shoes, which have decreased cushioning and/or heel elevation. However, transitioning from more traditional training shoes with heel-toe ramps of up to 15 mm to minimalist running shoes with a lower heel-toe ramp or even no heel-toe ramp may be challenging or problematic for some users, and pose the potential for injury.

For example, with a higher heel-toe ramp (e.g., 12-15 mm), the user's Achilles tendons and calf muscles are in a shortened position compared to the Achilles tendon and calf muscles with minimalist shoes, which are in a stretched or elongated position. This can cause problems as a user transitions the high heel-toe ramp downwards due to the increased stretching of the Achilles tendon and calf muscles. Furthermore, due to the different biomechanics of minimalist (or even barefoot) running, the distribution of stress during running in a minimalist shoe is also different from the distribution of stress during running in a traditional shoe. As the heel cushion/elevation no longer exists (or exists minimally) to absorb the shock of a strike during running, certain parts of the body, such as the ankle, calf, hip flexor muscles may experience increased stress from an increased load than to which they are accustomed. With the resultant decreased heel elevation, the user is also encouraged or tends to strike the ground mid-foot.

When transitioning from a heel strike to a mid-foot strike (e.g., ball-of-foot, metatarsus region) and particularly during high impact activities such as running, the user's mid-foot and/or metatarsal region may require a period of gradual adjustment to acclimate to the new stress experienced in that region. When a user initially transitions from a traditional running shoe to a minimalist type running shoe, the user may still be used to running by striking the ground heel first. However, the minimalist shoe may not have sufficient support or impact resistance in the heel region. Accordingly, due to the change in dynamics and stress of the foot when transitioning from a traditional running shoe (with a high heel-toe ramp angle) to a minimalist type shoe (with little or no heel-toe ramp angle), a gradual transition over a period of time such as a few weeks or months to adapt to minimalist type shoes may be beneficial. The present disclosure is directed to footwear, insoles, inserts, kits and methods which can be used to transition from footwear with a high heel-toe ramp of about 12 to about 15 mm (preferably 12-15 mm), to footwear with a lower (preferably 0 to about 4 mm or 4 mm) or no heel-toe ramp.

Prior art insoles have a fixed configuration targeted to specific areas of the foot rather than addressing the need for an insole which transitions the user to adapt to different footwear styles. With prior art insoles, a user may be forced to make multiple footwear insole purchases in order to transition to a desired heel-toe ramp angle. The present disclosure is also directed to insoles which can assist in providing support to areas of the foot that may receive increased stress due to a different movement of the foot, such as during barefoot or minimalist running. Prior art insoles have not taken into consideration acclimating a user's foot to varying stress impacts, such as when transitioning from a heel strike, to a mid-foot strike, which places additional stress previously not imposed on the mid-foot region. The exemplary embodiments of the present disclosure allow the user to maintain a more natural movement, yet also allowing transition to footwear which changes the high impact regions of the foot.

In one aspect, the present disclosure provides footwear, insoles and inserts having a region of adjustable thickness. It is noted that for the most part each instance of reference to an insole is also equally directed to embodiments of footwear and inserts. Accordingly, the insole may be a full insole, or a portion thereof, preferably having at least a heel region. The region of adjustable thickness may be at least a portion of the heel region, or at least a portion of the metatarsal region, or both. The region of adjustable thickness can be oriented on the surface side of the insole directed to the user's foot (not shown), but is preferably oriented to the surface side of the insole opposite to the side oriented to the user's foot (i.e., directed toward the running surface). By adjusting the thickness of one or more regions of the insole, the heel-toe ramp or relative elevation of the heel to non-heel portions of the foot, such as the toe region, can be adjusted to allow for changes in relative elevation of about 15 mm to about 2 mm. For example, a user may have an initial heel elevation (relative to the non-heel elevation) of about 15 mm, about 12 mm, or about 4 mm, from which the user wishes to transition to a target heel elevation (relative to the non-heel elevation) of about 4 mm, about 2 mm, and even 0 mm. The adjustment in elevation can be achieved by varying the thickness or number of a plurality of interchangeable inserts in the region of adjustable thickness or by using a material which can vary the elevation of the heel-toe ramp angle based on load, such as by using a material that can vary the elevation of specific parts of the insole as a function of load applied by a user. It is noted that while reducing the heel-toe ramp elevation is preferred, the present embodiments can also be used in reverse sequence to increase heel-toe ramp. This may occur if a user is using a minimalist elevation and wants to transition to a more traditional heel-toe elevation.

Again, while the term heel-toe ramp is used herein, it is noted that the term can equally mean the elevation difference between the user's heel and any non-heel portion of his foot. Further, the heel-toe ramp elevation is described for an unloaded insole for ease of understanding. It is noted that in some instances, the insole may be subject to some amount of compression that reduces the effective elevation differential while under load. This reduction in elevation can even vary by the variance in the load placed on the insole by the user. Reduction in elevation can also vary by the materials used in the insole. For example closed-cell foam, polyurethane, polyethylene, gels, thermoplastic rubber, and the like would compress less than an open foam composition. Accordingly, the disclosed elevation variance can be described as either the loaded (effective) or unloaded heel-toe variance, though herein the “effective” variance is considered in the dimensions provided herein.

Turning now to the figures, FIG. 1 illustrates one embodiment of a footwear insole 120 having an adjustable thickness feature which allows for an adjustment in the heel-toe ramp by changing the relative elevation of the heel and toe. Insole 120 has a top surface (see, 150 in FIG. 6) for receiving the bottom of a user's foot, and a bottom surface 130 opposite the top surface 150. It is noted that the insole 120 can include footwear or any of a variety of devices for placement within footwear, such as insoles, inserts, heel inserts, three-fourth length insoles, metatarsal inserts and the like. In other embodiments, the region of adjustable thickness of the insole 120 may be affixed to an existing shoe insole (not shown). As shown in FIG. 1, the insole 120 can have a first end (heel end) 124 and a second end 122 distal to the heel end 124 along a user's foot (e.g., a toe end, a metatarsal end, or a heel end), in FIG. 1, a toe end 122. A heel region 132 is adjacent to the first (heel) end 124 and a non-heel region 134 is adjacent to the second end (toe end) 122. The heel region 132 corresponds to region of the insole 120 that receives the weight load of the user from the back of the human foot below the ankle and behind the arch. The non-heel region 134 corresponds to the region extending distally beyond the heel region 132, for example, a metatarsal region. In the embodiment illustrated in FIGS. 1 and 2, both the heel region 132 and the metatarsal region 134 comprise a region of adjustable thickness, though as noted before, the region of adjustable thickness may be on either one of the heel region 132 or metatarsal region 134, or both, as shown in FIGS. 1-2. Heel toe ramp/elevation is preferably configured at the points of impact of the user's foot during ambulation, rather than at rest. The insole 120 can also have an interior edge 152 and exterior edge 154, wherein the interior edge 152 is configured to correspond to a user's arch region and the exterior edge 154 corresponds to an outside edge of a user's foot.

As shown in FIGS. 1 and 2, the region of adjustable thickness of the insole 120 may have one or more layered pads 126, 128 with, for example, multiple padding layers 140 a, 140 b, 140 c, 140 d as illustrated in FIG. 2. The padding layers 140 a, 140 b, 140 c, 140 d can be releasably joined by, for example, an adhesive 148 on one side of each respective padding layer 140 a, 140 b, 140 c, 140 d. The adhesive 148 can be any type of adhesive that adheres the layers 140 a, 140 b, 140 c, 140 d together and peels away only with an effort greater than found in normal use and does not leave a residue on the newly exposed layer. For example, a pressure sensitive adhesive with a release layer on the opposing side of the next layer can be used. It is also noted that other potential means of binding the padding layers may be considered, including for example, molecular attraction, static forces, surface tension, mechanical fasteners, such as hook and loop fasteners (such as those sold under the trade name VELCRO), and the like and combinations thereof. In some embodiments the inherent adhesiveness of the materials, such as some gels, may be used to hold the layered pads in place.

As shown, the layered pads 126, 128 have a top surface (not shown) affixed to the bottom surface 130 of the insole 120, and a bottom surface 142 a opposite the top surface. The bottom-most padding layer 140 a provides the bottom surface 142 a. It is again noted that the layered pads 126, 128 could optionally be affixed to the top surface 150 of the insole 120 such that they are on the side of the insole 120 in contact with the foot. In embodiments where layered pads are configured to be on the top surface, an optional cover layer could be placed over each layered pad and the top surface (not shown) of the insole 120. When the bottom-most padding layer 140 a is removed from the layered pad 126, 128 as illustrated in FIG. 2, a new bottom-most padding layer 140 b is revealed and provides a new bottom surface 142 b of the now thinner layered pad 126 and/or 128.

The bottom-most padding layer 140 a may be removed from or added to the layered pad 126, 128 as desired by peeling the bottom-most padding layer 140 a away from the padding layer 140 b adjacent to the bottom-most padding layer 140 a. One or more padding layers 140 b, 140 c may also be removed along with the bottom-most padding layer 140 a. The number of padding layers to be removed depends on the thickness of each of the padding layers 140 a, 140 b, 140 c, 140 d, and the desired heel-toe ramp/elevation variation. The multiple layers of padding 140 a, 140 b, 140 c, 140 d may be the same thickness, or may be different in thickness. In one embodiment, the region of adjustable thickness of the insole 120 may be a single layer of padding joined to the bottom surface 130 of the insole 120 by an adhesive 148. The layer of padding may be removed to change the thickness of the region of adjustable thickness. In one embodiment, each layer can be about 2 mm in thickness and formed from a non-compressible material (preferably about 0.5 to about 2.5 mm in thickness such as 0.5 mm to 2.5 mm). Thus for illustration, where the padding layers 140 a, 140 b, 140 c, 140 d are non-compressible, 6 padding layers can be included in the heel region to reduce the insole from a 12 mm ramp elevation difference between the heel and the metatarsal area of an unloaded insole to a neutral or equal elevation. As a further embodiment, each layer can represent a drop from the highest to the lowest ramp elevation in the range of 1 to 25 percent of the difference, and preferably 10 to 20 percent of the difference. Thus if each padding layer 140 a, 140 b, 140 c, 140 d represents 20 percent of the difference between the starting ramp elevation and the target elevation, then 5 padding layers would be indicated. Where the padding layers 140 a, 140 b, 140 c, 140 d are compressible, the thickness can be accordingly adjusted so that the effective layer thickness under anticipated load achieves the same dimensions as an unloaded non-compressible layer.

The multiple layers of padding may be joined by an adhesive 148 disposed between the padding layers 140 a, 140 b, 140 c, 140 d. The adhesive 148 may be a pressure sensitive adhesive or any other suitable adhesive known to one skilled in the art that can provide for adhesion between two padding layers, which can also be separated. In other embodiments, the multiple layers of padding may be formed from materials that provide adhesive or frictional properties to maintain the padding layers in contact with each other, yet provide for ease of separation from one another when needed. The padding layers may be formed from silicone, rubber, polyurethane, polyethylene, gels, closed cell foam, open cell foam, and the like with an adhesive and release layer disposed between the pads.

In the embodiments illustrated in FIGS. 1-2, the insole 120 comprising one or more layered pads is a full insole extending from a heel end 124 to a toe end 122. The region of adjustable thickness of the insole 120 may be the heel region 132, the non-heel region 134 (here, the metatarsal region), or both, in which case only the heel region 132, only the metatarsal region 134, or both, respectively, would comprise one or more of the layered pads. In other embodiments, the insole 120 can be configured to extend across only a portion of the foot. Exemplary insoles can be only for the heel portion (e.g., insole 820 of FIG. 8), a partial extension beyond the heel portion such as a three-fourth insole (insole 920 of FIG. 9), or only for the metatarsal portion (not shown). The heel portion insole 820, or the metatarsal portion insole 920, may comprise one or more layered pads, a cavity, or a non-Newtonian material (described in more detail below).

In another embodiment illustrated in FIGS. 3 and 4, the region of adjustable thickness of insole 220 comprises deformable brackets 222, 224 for receiving inserts 234 a, 232 a. Brackets 222, 224 are preferably disposed on the bottom surface 230 of the insole 220, and are configured in any suitable size or shape to removably engage the inserts 234 a, 232 a. The brackets 222, 224 may be formed as a unitary piece with the insole 220, or may be separately attached to the bottom surface 230 of the insole 220. The brackets 222, 224 may be made from the same or different material as the insole 220. Preferably, the brackets 222, 224 are of sufficient flexibility to accommodate inserts of varying thicknesses. Alternately, the inserts 234 a and 232 a may each have a peripheral lip 238 corresponding to the dimension of interior edge 240 of brackets 222 and 224. The brackets 222, 224 can range from rigid, e.g., no more than about 20 percent bending under a running load, or flexible to conform to the flexing of the user's foot during ambulation.

Inserts of varying thicknesses may be used in conjunction with the brackets 222, 224 to adjust the thickness of the region of adjustable thickness of the insole 220. A set of inserts 234 a, 234 b, 234 c, 232 a, 232 b, 232 c having thicknesses “a,” “b,” “c” as illustrated in FIG. 4 may be combined in a kit 236 with the insole 220. The user may then adjust the thickness of the metatarsal region 226, the heel region 228, or both, as desired. In one embodiment, the set of inserts 234 a, 234 b, 234 c for the metatarsal region 226 and the set of inserts 232 a, 232 b, 232 c for the heel region 228 have the same corresponding increments in thickness such that inserts 234 a and 232 a are of the same thickness “a,” inserts 234 b and 232 b are of the same thickness “b,” and so forth . . . , wherein “a” is greater than “b” which is greater than “c.” In other embodiments, the set of inserts 234 a, 234 b, 234 c for the metatarsal region 226 and the set of inserts 232 a, 232 b, 232 c for the heel region 228 may have different thicknesses. Any combination of thicknesses for the inserts 234 a, 234 b, 234 c metatarsal region 226 and the inserts 232 a, 232 b, 232 c for the heel region 228 can be used to provide a desired heel-toe ramp and the desired degree of gradual progression of heel-toe ramp.

In the embodiments illustrated in FIGS. 3-4, the insole 220 comprising brackets 222, 224 is a full insole extending from a heel end 124 to a toe end 122. The region of adjustable thickness of the insole 220 may be the heel region 228, the metatarsal region 226, or both, in which case only the heel region 228, only the metatarsal region 226, or both, respectively, would comprise the bracket for receiving an insert.

In other embodiments, an insole 820 extends along a portion of the foot, such as only along the heel portion as shown in FIG. 8, a three-fourth insole 920 extends along an extended heel portion as shown in FIG. 9, or an insole extends only along the metatarsal portion (not shown). The heel portion only, or the metatarsal portion only, may comprise a bracket for receiving an insert.

In yet another embodiment illustrated in FIGS. 5-7, the region of adjustable thickness of an insole 320 comprises a cavity 350 within the insole 320. The cavity 350 within the insole 320 has been shown in the heel region 328 only, but may be disposed within the metatarsal region 326 only (not shown), or within the metatarsal region 326 instead of or in addition to a cavity within the heel region 328. The cavity 350 is configured to receive an insert 352.

Inserts of varying thicknesses may be used in conjunction with the cavity 350 to adjust the thickness of the region of adjustable thickness of the insole 320. A set of inserts 352 a, 352 b, 352 c having thicknesses “a,” “b,” “c” as illustrated in FIG. 7 may be combined in a kit 336 with the insole 320 to permit a user to adjust the thickness of the region comprising the cavity 360, as desired. In one embodiment, the set of inserts 352 a, 352 b, 352 c have thicknesses “a,” “b,” and “c,” wherein “a” is greater than “b” which is greater than “c.” In other embodiments, the insole 320 may comprise a cavity 360 in both the metatarsal region and the heel region. A set of inserts for the metatarsal region 326 and the heel region 328 may be combined with the insole 320 to form a kit. Any combination of thicknesses for the metatarsal region inserts and the heel region inserts can be used to provide a desired heel-toe ramp/elevation and the desired degree of gradual progression of heel-toe ramp angles. The inserts 352 a, 352 b, 352 c can be rigid or semi-rigid as described above and can be non-compressible under user load during ambulation. It is also noted that the coefficient of friction for some materials, such as gels, will inherently be held in place while inserted into cavity 350.

In the embodiments illustrated in FIGS. 5-7, the insole 320 comprising a cavity 360 is a full insole extending from a heel end 324 to a toe end 322. The region of adjustable thickness of the insole 320 may be the heel region 328, the metatarsal region 326, or both, in which case only the heel region 328, only the metatarsal region 326, or both, respectively, would comprise the cavity 360. In other embodiments, the insole 320 may extend for a portion of the foot, such as only for the heel portion as shown in FIG. 8, an extended heel portion such as a three-fourth insole as shown in FIG. 9, or only for the metatarsal portion (not shown). The heel portion only, or the metatarsal portion only, may comprise the cavity 360. In some embodiments, when the cavity 360 is empty, the top and bottom surfaces of the cavity 360 are in contact with each other such that the cavity 360 is substantially closed. The cavity 360 is sufficiently elastic and flexible, and/or compressible to accept inserts of vary thicknesses and to conform to movement of the foot.

In another embodiment illustrated in FIGS. 10 and 11, a footwear insole 420 comprises a top surface (not shown) for receiving the bottom of a user's foot, a bottom surface 430 opposite the top surface, a heel end 424 and a toe end 422 on opposite ends of the insole 420. A heel region 432 is adjacent to the heel end 424 and a metatarsal region 434 is adjacent to the toe end 422. The metatarsal region 434 comprises a recessed region 436. An insert 460 of adjustable thickness 460 is disposed within the recessed region 430. The thickness of the insert 460 may be adjusted by using a material which varies in thickness in response to the rate of force applied. Such material which varies in thickness in response to the rate of force applied exhibit non-Newtonian characteristics.

Non-Newtonian materials are materials that exhibit non-linear stiffness in response to a strain rate. In other words, the non-Newtonian material can be flexible and compressible during periods of a first load such as a user walking or standing. In response to an increase strain from, for example from the increased load caused by a user running, the material can stiffen and have reduced or no-compressibility. The non-Newtonian material has a compressibility which changes in response to the rate of force applied, such that a lower application of force results in more compression of the region of adjustable thickness, resulting in a thinner material, and a higher application of force results in less compression of the region of adjustable thickness, resulting in a thicker material.

A non-Newtonian material may be a fluid, a gel, or a gel-like solid. Non-Newtonian materials may comprise polymers, such as silicone based polymers, which may be formed using siloxane, or poly-vinyl alcohol. Non-Newtonian materials may comprise lubricants materials such as oil, waxes, or grease. A non-Newtonian material may also include a filler type material used in combination with one or more of a polymeric material and lubricant, such as described in U.S. Pat. No. 6,701,529. One type of non-Newtonian material is known commercially as PORON XRD. The insert 460 can be flush or elevated beyond with the bottom surface 430 of the insole 420. In some embodiments, the insert 460 may protrude from the bottom surface 430 of the insole 420 such that the metatarsal region is thicker than the heel region. The insert 460 may be uniform in thickness, or may vary in thickness across the insert 460. The insert 460 may be any configuration, such as a discontinuous area, such as a series of concentric circles, for example, or a set of individual regions.

Accordingly, an insole having a non-Newtonian material can be used to provide cushioning and comfort during lower impact activities such as walking or standing. However, when a user engages in higher impact activity, the non-Newtonian nature of the insert provides the desired stiffness for more impact resistance. When running in a minimal-drop shoe with a lower heel, the foot becomes more naturally inclined to strike at the mid-foot region. Thus, the use of a metatarsal insert of a non-Newtonian material can provide the user with the impact resistance needed while the user is acclimating the metatarsal region to the new positioning of the foot in the minimal-drop shoe. For example, in FIG. 11, heel elevation 450 can be greater than the non-heel elevation 452 under a standing or walking load. The difference in the heel elevation 450 to non-heel elevation 452 can be reduced by increasing a dimension 454 if a user increases the load, such as by running, of the non-Newtonian insert 460, as described in more detail below. Thus, an insole comprising a non-Newtonian material in the metatarsal region provides the user with impact resistance during a foot-strike pattern wherein the foot strikes the ground first mid-foot, while still being able to maintain a relatively neutral heel-toe ramp/relative elevation due to the non-Newtonian material being compressible at low impacts.

The insole may also comprise a non-Newtonian insert in the heel region to assist the user in transitioning to a minimal-drop running shoe, wherein the user may still be inclined to strike the ground heel first, as is customary with traditional running shoes. Because the minimal-drop running shoe provides less cushioning in the heel, a user who has not acclimated to minimal-drop shoes and is still accustomed to a heel-strike would benefit from an insole having a non-Newtonian material in the heel which can provide the impact resistance needed for protection, yet without the need for thicker cushioning material which contributes to the steeper heel-toe ramp/relative elevation in more traditional shoes. In some embodiments, the non-Newtonian material in the heel is an insert or layer which may be removed once the user has acclimated to minimal-drop running shoes, and is no longer as inclined to strike heel first. The removal of the non-Newtonian material from the heel region allows the user to enjoy the remaining benefits of the insole without having to purchase a separate insole. Once the user has acclimated to a minimalist shoe, the user is less inclined to strike heel first and has developed a foot-strike pattern wherein the foot tends to strike mid-foot first. In other embodiments, the heel insert comprising a non-Newtonian material may be removed and transferred to the metatarsal region once the user has acclimated to minimal-drop running shoes, and is no longer as inclined to strike heel first. Thus, the placement of the non-Newtonian material in the metatarsal region provides support to the user in the region of higher impact now that the user has a mid-foot strike foot-strike pattern. The transfer of the non-Newtonian heel insert from the heel region to the metatarsal region may coincide with removing a Newtonian material from the metatarsal region and disposing the Newtonian material in the heel region such that the non-Newtonian and Newtonian inserts are interchangeable within the insole to accommodate the impact resistance needs of different foot-strike patterns.

In an alternative embodiment shown in FIG. 12, the insole 520 can be formed from a non-Newtonian material in only the non-heel region 534. As shown in FIG. 12, a side view of an insole 520 is shown having a non-Newtonian non-heel region 534 and a semi-rigid and semi-compressible heel region 532 such as, for example, a polyurethane gel. In use, the insole 520 could have a heel elevation dimension 550 (corresponding to the thickness of the heel region 532) that is greater than the dimension 552 of the non-heel region 534 (which can represent the elevation of the non-heel region 534 due to the amount of compression of the non-Newtonian material during standing or walking). During periods of high impact, such as running, which causes the non-heel region 534 to stiffen, the non-heel elevation can increase to a dimension 554, which is greater than the dimension 552, thus reducing the heel-toe ramp angle. For illustrative purposes only, during a standing load wherein the force on the insert is applied at a lower rate, (indicated at 540) the dimension 550 could be 12 mm and the dimension 552 could be 4 mm indicating a heel to non-heel elevation difference of 8 mm. If the user starts to run, the load (indicated at 560) could result in the heel maintaining a 12 mm elevation, but the higher rate of load applied to the non-heel region 534 will cause stiffening of the non-heel region, and compress the non-heel region less, such as to 10 mm instead of the 4 mm at standing loads. This effectively would reduce the heel to non-heel elevation variance to only 2 mm. Thus, the insole 520 could provide a heel-toe ramp typical of traditional shoes under lower rates of load, but convert to characteristics of a ‘minimalist’ shoe during higher rates of load, such as when running.

In some embodiments, the use of a non-Newtonian insert may be combined with any other embodiment to provide a region of adjustable thickness. In one approach, the regions of adjustable thicknesses can comprise non-Newtonian materials. In embodiments where the region of adjustable thickness comprises layered pads 126, 128 as illustrated, for example, in FIGS. 1 and 2, one or more layers of a layered pad, or a portion thereof, can comprise non-Newtonian materials. In other embodiments where the region of adjustable thickness comprises deformable brackets 222, 224 for receiving inserts 234 a, 232 a as illustrated, for example, in FIGS. 3 and 4, one or more of the inserts, or portions thereof, may comprise a Non-Newtonian material. In yet another embodiment where the region of adjustable thickness comprises a cavity 350 within the insole 320 configured to receive an insert 352, such as illustrated, for example, in FIGS. 5-7, one or more of the inserts 352, or portions thereof, can comprise non-Newtonian materials.

The present disclosure also provides a method for acclimating a user's foot to a target heel-toe ramp or relative elevation. One approach can involve the step of gradually adjusting the heel-toe ramp/relative elevation of an insole from a starting heel-toe ramp to a target heel-toe ramp. A gradual adjustment of the heel-toe incline can provide an insole with a top surface for receiving the bottom of a user's feet, a bottom surface opposite the top surface, a heel end and a toe end on opposite ends of the insole. A heel region is adjacent to the heel end and a metatarsal region is adjacent to the toe end. At least one of a portion of the heel region or a portion of the metatarsal region is a region adjustable in thickness. The thickness of at least one of a portion of the heel region or a portion of the metatarsal region is adjusted to provide for a first desired heel-toe ramp angle. The insole is used with footwear for a first duration of time sufficient for a user's foot to acclimate to the first desired heel-toe ramp angle. The thickness of at least one of a portion of the heel region or a portion of the metatarsal region is adjusted again to provide for a second desired heel-toe ramp angle different from the first desired heel-toe ramp angle. The insole is then used with footwear for a second duration of time sufficient for a user's foot to acclimate to the second desired heel-toe ramp angle.

The adjustment of the region of adjustable thickness to acclimate a user's foot to a target heel-toe ramp angle may be by any of the adjustment mechanisms described above with respect to FIGS. 1-7. The gradual adjustment of the heel-toe ramp angle to acclimate a user's foot to a target heel-toe ramp angle may also comprise providing an insole which extends for a portion of the foot, such as the heel portion, an extended heel portion, or a metatarsal portion. The partial insoles, as shown, for example, in FIGS. 8 and 9, comprise a region of adjustable thickness which may be adjusted by any of the adjustment mechanisms described above with respect to FIGS. 1-7. It is noted though that in a kit form, for example, the heel insert of FIG. 8 and the ¾ insole of FIG. 9 can be formed into a set of fixed thickness inserts and insoles that vary in 2 mm. In this instance the user would swap out the entire insert or insole in the kit with another insert or insole in the set when a change in heel-toe ramp angle is desired. The set of insoles or inserts in these kits can be organized or identified by their thickness by imprinting indicia (such as 2 mm, 4 mm, 6 mm, etc.) on insert or insole; varying colors, and the like and combinations thereof. Likewise left and right mirror images of each of the inserts and insoles can be similarly identified. It is noted that these identifying features could apply to all the embodiments described herein.

A user may desire to gradually transition from footwear having a steep heel-toe ramp angle as described above to footwear having a lower heel-toe ramp angle using the insoles provided in the disclosure. For example, a user with feet accustomed to the steeper heel-toe ramp angle of a traditional running shoe may desire to switch to a minimalist-type running shoe with less heel support and elevation and a lower heel-toe ramp angle. However, the minimalist type running shoe with the lower heel support places the user's heel in a lower position than the user is accustomed to. This lowered positioning may extend the Achilles tendon and the calf muscle in a manner with which the user is not accustomed, and posing the potential for injury. To reduce the potential for injury, the user may find it easier to use an insole to help gradually acclimate the foot, the tendons, the calf muscles, and other muscles to their newer position. The user may also desire to have more support or impact resistance in the heel during an initial transition period wherein the user is more inclined to have a heel-strike type foot-strike pattern, and have more support or impact resistance in the mid-foot area after the initial transition period wherein the user has adjusted to a mid-foot type foot-strike pattern.

In other embodiments, the three-fourths insole 920 and heel insert 820 may be completely formed to a specific heel thickness and sold individually or as a kit. In these embodiments, the user may completely replace the insole or heel insert to stepwise increase or decrease the heel height dimension. Such inserts can be in addition to an insert already provided within the shoe and can be placed either above or below the provided insert. For example, a user accustomed to a 12 mm heel-toe ramp reduction of 12 mm can purchase footwear having a heel-toe ramp of zero mm (i.e., neutral or minimalist) and insert an insert or insole having a 12 mm heel thickness and after a period of time of adjustment replacing it, for example, with one that is 10 mm, and repeating until the desired height difference is achieved.

The insoles comprising regions of adjustable thickness may be used to gradually acclimate a user to footwear with a different heel-toe ramp angle. For transitioning from footwear with a steep heel-toe ramp angle to footwear with a less steep heel-toe ramp angle, the insole may be used with the footwear having the lower heel-toe ramp angle and allowing the user to gradually reduce the thickness of the heel to gradually reduce the relative elevation of the toe and the heel. The gradual reduction of the relative elevation of the toe and heel can also be achieved by adjusting both the thickness of the heel region and the metatarsal region.

Another way to transition from a steep heel-toe ramp angle to a less steep heel-toe ramp angle would be to use one or more of the insoles described above with footwear having the steeper heel-toe ramp angle and allowing the user to gradually increase the thickness of the metatarsal region to gradually reduce the relative elevation of the toe and the heel while ambulating. The gradual reduction of the relative elevation of the toe and heel can also be achieved by adjusting both the thickness of the heel region and the metatarsal region.

Also provided by the present disclosure is a method for acclimating a user's foot from a first foot-strike pattern to a second foot-strike pattern comprising providing an insole with a heel region and a metatarsal region wherein at least a portion of the heel region of a portion of the metatarsal region is a region of adjustable thickness which changes in response to the rate of force applied. The region of adjustable thickness being located at a first location where the foot first strikes the ground during the first foot-strike pattern. The user uses the insole with footwear for a first duration of time sufficient for a user's foot to acclimate to a second foot-strike pattern having a second location where the foot first strikes the ground. For example, a user who wishes to transition form a traditional type running shoe having cushioning in the heel region to a more minimalist type shoe would benefit from the initial placement of an insert comprising a non-Newtonian material in the heel region. During an initial transition period where the user is still inclined to have a heel-strike type foot-strike pattern, the user may desire to have more support or impact resistance in the heel region. Once the user has acclimated to a minimalist type shoe which encourages a mid-foot strike type of foot-strike pattern, the user may find that impact resistance type cushioning is no longer needed in the heel region. In some embodiments, the insert in the heel region comprising a non-Newtonian material to provide impact resistance may be removed once the user has transitioned from a first foot-strike pattern (such as a heel-strike) to a second foot-strike pattern (such as a mid-foot strike). In other embodiments, because the user has transitioned to a second foot-strike pattern which is a mid-foot strike, any insert in the mid-foot region may be replaced with the non-Newtonian insert from the heel region to transform the insole to one providing impact resistance during a mid-foot strike foot-strike pattern.

From the foregoing, it will be observed that numerous variations and modifications may be effected without departing from the spirit and scope of the disclosure. It is to be understood that no limitation with respect to the specific embodiments illustrated herein is intended or should be inferred. 

1. A footwear insole having an adjustable thickness, comprising: a top surface for receiving a bottom of a user's foot, and a bottom surface opposite the top surface; the insole configured to extend along a portion of the user's foot; wherein at least one portion of the insole is a region of adjustable thickness.
 2. The insole of claim 1 wherein the insole comprises a heel region.
 3. The insole of claim 2 wherein the insole extends from the heel region to a non-heel region comprising at least a portion of an arch region.
 4. The insole of claim 3 wherein the insole further comprises a metatarsal region.
 5. The insole of claim 1, further comprising: a heel end and a toe end on opposite ends of the insole; and a heel region adjacent to the heel end and a metatarsal region adjacent to the toe end; wherein at least a portion of at least one of the heel region and the metatarsal region is a region of adjustable thickness.
 6. The insole of claim 5 comprising two regions of adjustable thickness, wherein the heel region comprises one region of adjustable thickness and the non-heel region comprises the second region of adjustable thickness.
 7. The insole of claim 1, wherein the region of adjustable thickness comprises a layered pad, the layered pad extending from the bottom surface of the insole, the layered pad comprising a plurality of padding layers disposed in contact with each other, the padding layers having a layer of adhesive therebetween.
 8. The insole of claim 1, wherein the region of adjustable thickness comprises a bracket for receiving an insert, the bracket configured to slidably engage the insert.
 9. A kit for acclimating a user's foot to a desired heel-toe ramp, comprising the insole of claim 8 and one or more inserts of varying thickness.
 10. The insole of claim 1, wherein the region of adjustable thickness comprises a cavity within a heel region of the insole, the cavity configured to receive an insert.
 11. A kit for acclimating a user's foot to a desired heel-toe ramp, comprising the insole of claim 10 and one or more inserts of varying thickness.
 12. The insole of claim 1, wherein the region of adjustable thickness has a thickness which can be adjusted from between 12 mm to 0 mm in 2 mm increments.
 13. The insole of claim 1 wherein the region of adjustable thickness is adapted to adjust in response to a rate of force applied, such that a lower rate of force applied results in more compression of the region of adjustable thickness and a higher rate of force applied results in less compression of the region of adjustable thickness.
 14. The insole of claim 13 further comprising a recessed region and an insert, wherein the region of adjustable thickness is an insert disposed within the recessed region.
 15. A method for acclimating a user's foot to a target heel-toe ramp, the method comprising: providing an insole with a top surface for receiving a bottom of a user's foot and a bottom surface opposite the top surface, the insole extending along a portion of the user's foot, at least a portion of the insole having a region of adjustable thickness; and gradually adjusting the heel-toe ramp of the insole from a starting heel-toe ramp to a target heel-toe ramp.
 16. The method of claim 15 wherein the insole has a heel end and a toe end on opposite ends of the insole, a heel region adjacent to the heel, end and a metatarsal region adjacent to the toe end; wherein at least one of a portion of the heel region and a portion of the metatarsal region is the region of adjustable thickness.
 17. The method of claim 16 comprising two regions of adjustable thickness, wherein the heel region comprises one region of adjustable thickness and the non-heel region comprises the second region of adjustable thickness.
 18. The method of claim 15, wherein the region of adjustable thickness comprises a layered pad, the layered pad extending from the bottom surface of the insole, the layered pad comprising a plurality of padding layers disposed in contact with each other, the padding layers having a layer of adhesive therebetween.
 19. The method of claim 15 wherein the region of adjustable thickness comprises a deformable bracket for receiving an insert, the bracket configured to slidably engage an insert.
 20. The method of claim 15 wherein the region of adjustable thickness comprises a cavity within the heel region of the insole, the cavity configured to receive an insert.
 21. The method of claim 15 wherein the heel-toe ramp angle is adjustable from 12 mm to 0 mm in 2 mm increments.
 22. The method of claim 15 wherein the region of adjustable thickness is adapted to adjust in response to a rate of force applied, such that a lower rate of force applied results in more compression of the region of adjustable thickness and a higher rate of force applied results in less compression of the region of adjustable thickness.
 23. The method of claim 15 wherein the step of gradually adjusting the heel-toe ramp angle comprises: adjusting a thickness of the region of adjustable thickness to provide a first desired heel-toe ramp angle; using the insole with footwear for a first duration of time sufficient for a user's foot to acclimate to the first desired heel-toe ramp angle; adjusting the thickness of the region of adjustable thickness to provide for a second desired heel-toe ramp angle different from the first desired heel-toe ramp angle; and using the insole with footwear for a second duration of time sufficient for a user's foot to acclimate to the second desired heel-toe ramp angle.
 24. A method for acclimating a user's foot from a first foot-strike pattern to a second foot-strike pattern, the method comprising: providing an insole with a top surface for receiving a bottom of a user's foot, a bottom surface opposite the top surface, a heel end and a toe end on opposite ends of the insole, a heel region adjacent to the heel end, and a metatarsal region adjacent to the toe end; wherein at least one of a portion of the heel region and a portion of the metatarsal region is a region of adjustable thickness, the region of adjustable thickness is adapted to adjust in response to a rate of force applied, such that a lower rate of force applied results in more compression of the region of adjustable thickness and a higher rate of force applied results in less compression of the region of adjustable thickness, the region of adjustable thickness being located at a first location where the foot first strikes the ground during a first foot-strike pattern; and using the insole with footwear for a first duration of time sufficient for a user's foot to acclimate to a second foot-strike pattern having a second location where the foot first strikes the ground.
 25. The method of claim 24 further comprising the step of: removing the region of adjustable thickness from its first location to the second location when the user's foot has acclimated to the second foot-strike pattern.
 26. The method of claim 24 further comprising removing the insole from the footwear once the user has acclimated to the second foot-strike pattern.
 27. The method of claim 24 wherein the first foot strike pattern is a pattern wherein the heel strikes the ground first, and the second foot-strike pattern is a pattern where the mid-foot strikes the ground first.
 28. Footwear, comprising: an insole having a top surface for receiving a bottom of a user's foot, and a bottom surface opposite the top surface; a heel end and a toe end on opposite ends of the insole; a heel region adjacent to the heel end and a metatarsal region adjacent to the toe end; a recessed region in at least one of the heel region and the metatarsal region; and an insert disposed within the at least one recessed region, wherein the insert comprises a non-Newtonian material. 